oxalyl dichloride; dimethyl sulfoxide; triethylamine in dichloromethane T=-60°C;

trifluoroacetic acid 0.25 h; Heating;

1: 61 percent / hexamethylenetetramine, glacial acetic acid, sulfuric acid / 18 h / 25 °C 2: 80 percent / potassium carbonate, N, N-dimethylformamide / 1.5 h / Heating 3: 49 percent / trifluoroacetic acid / 0.25 h / Heating View Scheme

1: 84 percent / m-chloroperbenzoic acid / CH2Cl2 / 0 deg C to 22 deg C, 22 h 2: 75 percent / potassium hydroxide, water / dimethylsulfoxide / 3 h / 23 °C 3: 96 percent / triethylamine, 4-dimethylaminopyridine / CH2Cl2 / 8 h / 22 °C 4: 91 percent / N-bromosuccinimide, benzoylperoxide / CCl4 / Heating; Irradiation 5: sodium cyanoborohydride, hexamethylphosphoramide / 10 h / 70 °C 6: 93 percent / potassium carbonate / methanol / 2 h / 22 °C 7: 81 percent / 2 M oxalyl chloride, dimethyl sulfoxide, triethylamine / CH2Cl2 / -60 °C View Scheme

1: 82 percent / N,N-dimethylaniline / 2.5 h / 193 °C 2: 84 percent / m-chloroperbenzoic acid / CH2Cl2 / 0 deg C to 22 deg C, 22 h 3: 75 percent / potassium hydroxide, water / dimethylsulfoxide / 3 h / 23 °C 4: 96 percent / triethylamine, 4-dimethylaminopyridine / CH2Cl2 / 8 h / 22 °C 5: 91 percent / N-bromosuccinimide, benzoylperoxide / CCl4 / Heating; Irradiation 6: sodium cyanoborohydride, hexamethylphosphoramide / 10 h / 70 °C 7: 93 percent / potassium carbonate / methanol / 2 h / 22 °C 8: 81 percent / 2 M oxalyl chloride, dimethyl sulfoxide, triethylamine / CH2Cl2 / -60 °C View Scheme

1: 96 percent / triethylamine, 4-dimethylaminopyridine / CH2Cl2 / 8 h / 22 °C 2: 91 percent / N-bromosuccinimide, benzoylperoxide / CCl4 / Heating; Irradiation 3: sodium cyanoborohydride, hexamethylphosphoramide / 10 h / 70 °C 4: 93 percent / potassium carbonate / methanol / 2 h / 22 °C 5: 81 percent / 2 M oxalyl chloride, dimethyl sulfoxide, triethylamine / CH2Cl2 / -60 °C View Scheme

1: 75 percent / potassium hydroxide, water / dimethylsulfoxide / 3 h / 23 °C 2: 96 percent / triethylamine, 4-dimethylaminopyridine / CH2Cl2 / 8 h / 22 °C 3: 91 percent / N-bromosuccinimide, benzoylperoxide / CCl4 / Heating; Irradiation 4: sodium cyanoborohydride, hexamethylphosphoramide / 10 h / 70 °C 5: 93 percent / potassium carbonate / methanol / 2 h / 22 °C 6: 81 percent / 2 M oxalyl chloride, dimethyl sulfoxide, triethylamine / CH2Cl2 / -60 °C View Scheme

1: 91 percent / N-bromosuccinimide, benzoylperoxide / CCl4 / Heating; Irradiation 2: sodium cyanoborohydride, hexamethylphosphoramide / 10 h / 70 °C 3: 93 percent / potassium carbonate / methanol / 2 h / 22 °C 4: 81 percent / 2 M oxalyl chloride, dimethyl sulfoxide, triethylamine / CH2Cl2 / -60 °C View Scheme

1: 93 percent / potassium carbonate / methanol / 2 h / 22 °C 2: 81 percent / 2 M oxalyl chloride, dimethyl sulfoxide, triethylamine / CH2Cl2 / -60 °C View Scheme

1: sodium cyanoborohydride, hexamethylphosphoramide / 10 h / 70 °C 2: 93 percent / potassium carbonate / methanol / 2 h / 22 °C 3: 81 percent / 2 M oxalyl chloride, dimethyl sulfoxide, triethylamine / CH2Cl2 / -60 °C View Scheme